1. Field of the Invention
The present invention relates to resinous blends of modified epoxy resins and acrylic resins. More specifically, the present invention relates to water-based coating compositions of resinous blends which have been found to be very suitable for can or coil coatings, particularly in the electrodeposition mode.
2. Brief Description of the Prior Art
Resinous blends containing acrylic and/or epoxy resins are generally known in the art. It is, however, the case generally that resinous blends are often limited in their use because of problems of incompatibility. In the area of can and coil coatings, the art has disclosed the use of resinous blends. In a rather pertinent example, the art has disclosed a method for coil coating by means of electrodeposition comprising passing a flat metal sheet in an electrodeposition bath comprising a water-soluble resinous coating material and a water-insoluble emulsified resinous material. However, many of the electrodepositable compositions in the area of can or coil coatings do not give commercially usable coatings. Electrodeposition of many coatings even where successful is attended by shortcomings pertinent among which is continuity of coatings, particularly those formed over short deposition times of about 1 to 10 seconds.
In the area of can coatings in particular, these shortcomings are unacceptable. Coatings intended for use in food and beverage industries must meet stringent requirements in order to be useful for this purpose. The coating must adhere well to the base metal and must possess a certain set of flexibility, extensibility and adhesion characteristics so as to withstand the processing of the container itself. The coating must also be able to resist heat which can be encountered during processing of the container. Additionally, the coating itself must not affect the taste of a food or beverage which is put into the coated container.
Art-known electrocoats and processes thereof have not met the stringent requirements, particularly those that relate to continuous coatings. By the present invention, there is provided a resinous blend which can be used in can and/or coil coatings.